Revision as of 11:24, 22 August 2012

Contents

Introduction

Merging models is a common need in model-based activities, not only for version control but for model manipulation in general. However, merging models is much more complex than merging source code. Since EMF models are rich data structures with constraints and behavior, merging them consistently is a delicate problem.

EMF Diff/Merge aims to help solve that problem. The scope of EMF Diff/Merge covers:

A lightweight, configurable engine for comparing and merging EMF models in 2-way and 3-way (with common ancestor) configurations.

Matching of model elements by ID, where an ID can be any "signature" that uniquely identifies the element within its scope: Ecore ID, XML ID, qualified name, location in model tree, etc.

A simple GUI with reusable UI components.

The tool is intended to satisfy the following requirements:

It must support the comparison and merge of large models (scalability, reliability).

The order in which differences are merged must have no impact.

The consistency of the model being merged must be preserved whenever possible, by automatically merging interdependent differences together.

The final goal is to obtain a mature, versatile software building block for multiple usages: version control, incremental model transformations, model refactoring, etc.